I recently read a post that suggested that the auxiliary fan cooling the ac condensor on the 81-85 300sd are inadequate. Is there any truth to that?

I ask because I have an 85 300SD with new compressor(R4 unit with 134) and drier. Freon levels are fine and no apparent leaks.

The A/C blows like a Camry(great AC) when I am driving down the road, yet at idle, it seems to blow less cold. I have experienced similar situations with Ford and an additional fan has worked out. If that is the case, do I have to add an additional relay to install?

I have also read when the system is converted to 134 that a high or low pressure switch needs to changed, that would kick in the aux fan sooner/stronger.

I tried to search and couldn't find the relative posts.

Any advice appreciated.

I've also noticed that on one of my ( non M-B) vehicles, the A/C is not as cold when I'm in traffic. I, too, have considered adding an aux electric fan. I thought about wiring to the compressor clutch, maybe using a relay to keep the load off of the clutch switch. That way, whenever the compressor comes on, the fan runs, too. You could also add a manual switch in parallel so that you could turn it on any time you needed it.
Keep us informed on your progress.
Michael